U.S. patent application number 16/081181 was filed with the patent office on 2019-02-21 for hot extruded material for cylindrical sputtering target and method of manufacturing cylindrical sputtering target.
This patent application is currently assigned to MITSUBISHI MATERIALS CORPORATION. The applicant listed for this patent is MITSUBISHI MATERIALS CORPORATION. Invention is credited to Satoshi Kumagai, Michiaki Ohto, Akira Sakurai.
Application Number | 20190055625 16/081181 |
Document ID | / |
Family ID | 61831685 |
Filed Date | 2019-02-21 |
United States Patent
Application |
20190055625 |
Kind Code |
A1 |
Ohto; Michiaki ; et
al. |
February 21, 2019 |
HOT EXTRUDED MATERIAL FOR CYLINDRICAL SPUTTERING TARGET AND METHOD
OF MANUFACTURING CYLINDRICAL SPUTTERING TARGET
Abstract
A hot extruded material for a cylindrical sputtering target is
provided, in which a purity of copper is in a range of 99.99 mass %
to 99.9995 mass %, an Al content is 0.5 mass ppm or lower, a Si
content is 1 mass ppm or lower, a C content is 1 mass ppm or lower,
an O content is 2 mass ppm or lower, a H content is 1 mass ppm or
lower, and a S content is 5 mass ppm or lower, and an average
crystal grain size measured at 36 positions in total is in a range
of 10 .mu.m to 110 .mu.m and a Vickers hardness measured at the 36
positions in total is in a range of 40 Hv to 100 Hv, the 36
positions being selected by obtaining three cross-sections
perpendicular to an axis O direction from one end portion, an
intermediate portion, and another end portion in the axis O
direction, setting four positions in a peripheral direction from
each of the three cross-sections, and setting three positions in
each of the four positions, the three positions including a surface
part, a radially 1/4 position from the surface part, and a radially
1/2 position from the surface part.
Inventors: |
Ohto; Michiaki; (Iwaki-shi,
JP) ; Kumagai; Satoshi; (Osaka, JP) ; Sakurai;
Akira; (Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MITSUBISHI MATERIALS CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
MITSUBISHI MATERIALS
CORPORATION
Tokyo
JP
|
Family ID: |
61831685 |
Appl. No.: |
16/081181 |
Filed: |
September 26, 2017 |
PCT Filed: |
September 26, 2017 |
PCT NO: |
PCT/JP2017/034742 |
371 Date: |
August 30, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C22C 9/00 20130101; C22C
9/01 20130101; C22C 9/06 20130101; C22F 1/08 20130101; C23C 14/34
20130101; C22C 9/02 20130101; C23C 14/3414 20130101; C22C 9/08
20130101; H01L 21/285 20130101; H01J 37/3426 20130101 |
International
Class: |
C22C 9/01 20060101
C22C009/01; H01J 37/34 20060101 H01J037/34; C23C 14/34 20060101
C23C014/34; H01L 21/285 20060101 H01L021/285; C22F 1/08 20060101
C22F001/08 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 7, 2016 |
JP |
2016-199009 |
Claims
1. A hot extruded material for a cylindrical sputtering target,
wherein a purity of copper is in a range of 99.99 mass % to 99.9995
mass %, an Al content is 0.5 mass ppm or lower, a Si content is 1
mass ppm or lower, a C content is 1 mass ppm or lower, an O content
is 2 mass ppm or lower, a H content is 1 mass ppm or lower, and a S
content is 5 mass ppm or lower, and an average crystal grain size
measured at 36 positions in total is in a range of 10 .mu.m to 110
.mu.m and a Vickers hardness measured at the 36 positions in total
is in a range of 40 Hv to 100 Hv, the 36 positions being selected
by obtaining three cross-sections perpendicular to an axis
direction from one end portion, an intermediate portion, and
another end portion in the axis direction, setting four positions
in a peripheral direction from each of the three cross-sections,
and setting three positions in each of the four positions, the
three positions including a surface part, a radially 1/4 position
from the surface part, and a radially 1/2 position from the surface
part.
2. The hot extruded material for a cylindrical sputtering target
according to claim 1, wherein a total content of one element or two
or more elements selected from the group consisting of Ag, As, Pb,
Sb, Bi, Cd, Sn, Ni, and Fe is in a range of 10 mass ppm to 50 mass
ppm.
3. The hot extruded material for a cylindrical sputtering target
according to claim 1, wherein a weight ratio of acid-insoluble
residues is 1.5 mass ppm or lower, and the number of acid-insoluble
residues having a grain size of 5 .mu.m or more is 15000
residues/Cu 1 g or less.
4. The hot extruded material for a cylindrical sputtering target
according to claim 1, wherein an outer diameter is 140 mm to 200
mm, an inner diameter is 80 mm to 140 mm, and a length is 900 mm to
4000 mm, and a maximum bending amount is 1.5 mm or less.
5. A method of manufacturing a cylindrical sputtering target, the
method comprising: a melting and casting step of obtaining an ingot
in which a purity of copper is 99.99 mass % to 99.9995 mass %, an
Al content is 0.5 mass ppm or lower, a Si content is 1 mass ppm or
lower, a C content is 1 mass ppm or lower, an O content is 2 mass
ppm or lower, a H content is 1 mass ppm or lower, and a S content
is 5 mass ppm or lower; a hot extrusion step of performing hot
extrusion on the ingot to obtain a hot extruded material for a
cylindrical sputtering target; and a machining step of performing
machining on the hot extruded material for a cylindrical sputtering
target.
Description
TECHNICAL FIELD
[0001] The present invention relates to a hot extruded material for
a cylindrical sputtering target that is a material of a cylindrical
sputtering target used during sputtering of a thin film formed of
copper, and a method of manufacturing a cylindrical sputtering
target.
[0002] Priority is claimed on Japanese Patent Application No.
2016-199009, filed on Oct. 7, 2016, the content of which is
incorporated herein by reference.
BACKGROUND ART
[0003] In the related art, Al or an Al alloy is widely used as a
wiring film for a flat panel display such as a liquid crystal or
organic EL panel or for a touch panel. Recently, the size (width)
and thickness of a wiring film have been reduced, and thus a wiring
film having a lower specific resistance than that in the related
art has been required.
[0004] Therefore, along with the reduction in size and thickness of
the wiring film, a wiring film formed of copper that is a material
having a lower specific resistance than Al or an Al alloy is
provided.
[0005] In a case where a wiring film (thin film) formed of copper
is formed on a substrate, a sputtering method using a sputtering
target is typically adopted.
[0006] As the sputtering target, for example, a flat sputtering
target described in Patent Document 1, or a cylindrical sputtering
target described in Patent Documents 2 and 3 is proposed.
[0007] An outer peripheral surface of the cylindrical sputtering
target is a sputtering surface, and sputtering is performed while
rotating the cylindrical sputtering target. Therefore, the
cylindrical sputtering target is more suitable for continuous film
formation as compared to a case where the flat sputtering target is
used, and has an advantageous effect in that the efficiency in use
of the target is excellent.
CITATION LIST
Patent Literature
[0008] [Patent Document 1] Japanese Patent No. 4974198
[0009] [Patent Document 2] Japanese Unexamined Patent Application,
First Publication No. 2013-057112
[0010] [Patent Document 3] Japanese Unexamined Patent Application,
First Publication No. 2013-185238
DISCLOSURE OF INVENTION
Technical Problem
[0011] As described in Patent Documents 2 and 3, the cylindrical
sputtering target is manufactured using a manufacturing method
including a melting and casting step, a hot working (extrusion)
step, a cold working (expansion) step, and a heat treatment
step.
[0012] Recently, the size of a substrate has increased, and a
longer lifetime than that in the related art has been required for
the cylindrical sputtering target.
[0013] In order to improve the lifetime of the cylindrical
sputtering target, it is necessary to manufacture a thick material
having a large difference between an outer diameter and an inner
diameter.
[0014] In a case where cold working (expansion) is performed as
described in Patent Documents 2 and 3, warping or bending occurs
during working. Therefore, in order to correct warping or bending,
it is necessary to cut an outer peripheral surface or an inner
peripheral surface. Therefore, it is difficult to provide a thick
cylindrical sputtering target.
[0015] Further, since a hot extruded material formed of pure copper
is relatively soft, bending or thickness deviation is likely to
occur. In addition, since the recrystallization temperature is low,
the progress of recrystallization varies in an axis direction, and
characteristics are not stable. Therefore, a hot extruded material
cannot be used as a sputtering target without performing cold
working.
[0016] In addition, in a case where a film is formed using a
sputtering target, foreign matter in the sputtering target may
cause abnormal discharge (arcing) to occur. Therefore, there may be
a case where a uniform wiring film cannot be formed. Abnormal
discharge is a phenomenon in which a much higher current than that
during normal sputtering suddenly flows such that abnormally large
discharge occurs. In a case where this abnormal discharge occurs,
particle formation may occur, or the thickness of a wiring film may
be uneven. Accordingly, it is desirable to avoid abnormal discharge
as much as possible during film formation.
[0017] The present invention has been made in consideration of the
above-described circumstances, and an object thereof is to provide
a thick and long-life hot extruded material for a cylindrical
sputtering target with which the occurrence of abnormal discharge
is suppressed such that a film can be stably formed, and a method
of manufacturing a cylindrical sputtering target using the hot
extruded material for a cylindrical sputtering target.
Solution to Problem
[0018] In order to achieve the object, according to the present
invention, a hot extruded material for a cylindrical sputtering
target is provided, in which a purity of copper is in a range of
99.99 mass % to 99.9995 mass %, an Al content is 0.5 mass ppm or
lower, a Si content is 1 mass ppm or lower, a C content is 1 mass
ppm or lower, an O content is 2 mass ppm or lower, a H content is 1
mass ppm or lower, and a S content is 5 mass ppm or lower, and an
average crystal grain size measured at 36 positions in total is in
a range of 10 .mu.m to 110 .mu.m and a Vickers hardness measured at
the 36 positions in total is in a range of 40 Hv to 100 Hv, the 36
positions being selected by obtaining three cross-sections
perpendicular to an axis direction from one end portion, an
intermediate portion, and another end portion in the axis
direction, setting four positions in a peripheral direction from
each of the three cross-sections, and setting three positions in
each of the four positions, the three positions including a surface
part, a radially 1/4 position from the surface part, and a radially
1/2 position from the surface part.
[0019] The purity of copper in the present invention is a numerical
value excluding gas components such as O, H, N, S, and C.
[0020] In the hot extruded material for a cylindrical sputtering
target according to the present invention having the
above-described configuration, an average crystal grain size
measured at 36 positions in total (three cross-section.times.four
positions in a peripheral direction.times.three positions=36
positions) in a range of 10 .mu.m to 110 .mu.m and a Vickers
hardness measured at the 36 positions in total is in a range of 40
Hv to 100 Hv, the 36 positions being selected by obtaining three
cross-sections perpendicular to an axis direction from one end
portion, an intermediate portion, and another end portion in the
axis direction, setting four positions in a peripheral direction
from each of the three cross-sections, and setting three positions
in each of the four positions, the three positions including a
surface part, a radially 1/4 position from the surface part, and a
radially 1/2 position from the surface part. Therefore, there is no
variation in crystal grain size and hardness in the axis direction
and the radial direction, and the hot extruded material for a
cylindrical sputtering target can be used as a cylindrical
sputtering target only after performing machining thereon.
[0021] In addition, cold working (expansion) is not necessary.
Therefore, a thick cylindrical sputtering target can be obtained,
and the lifetime thereof can be increased.
[0022] In addition, the Al content is 0.5 mass ppm or lower, the Si
content is 1 mass ppm or lower, the C content is 1 mass ppm or
lower, the O content is 2 mass ppm or lower, the H content is 1
mass ppm or lower, and the S content is 5 mass ppm or lower.
Therefore, the occurrence of abnormal discharge caused by
impurities can be reliably reduced.
[0023] In the hot extruded material for a cylindrical sputtering
target according to the present invention, it is preferable that a
total content of one element or two or more elements selected from
the group consisting of Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe be
in a range of 10 mass ppm to 50 mass ppm.
[0024] In this case, the total content of one element or two or
more elements selected from the group consisting of Ag, As, Pb, Sb,
Bi, Cd, Sn, Ni, and Fe is 10 mass ppm or higher. Therefore, the
crystal grain size can be reduced, and a variation in average
crystal grain size and Vickers hardness can be suppressed. On the
other hand, the total content of one element or two or more
elements selected from the group consisting of Ag, As, Pb, Sb, Bi,
Cd, Sn, Ni, and Fe is limited to be 50 mass ppm or lower.
Therefore, the occurrence of abnormal discharge caused by the
elements can be reliably reduced.
[0025] In addition, in the hot extruded material for a cylindrical
sputtering target according to the present invention, it is
preferable that a weight ratio of acid-insoluble residues be 1.5
mass ppm or lower and the number of acid-insoluble residues having
a grain size of 5 .mu.m or more be 15000 residues/Cu 1 g or
less.
[0026] In this case, the weight ratio of acid-insoluble residues is
in a range of 0.2 mass ppm to 1.5 mass ppm, and the number of
acid-insoluble residues having a grain size of 5 .mu.m or more is
limited to be 15000 residues/Cu 1 g or less. Therefore, particle
formation can be suppressed during film formation.
[0027] Further, in the hot extruded material for a cylindrical
sputtering target according to the present invention, it is
preferable that an outer diameter be 140 mm to 200 mm, an inner
diameter be 80 mm to 140 mm, a length be 900 mm to 4000 mm, and a
maximum bending amount be 1.5 mm or less.
[0028] In this case, the outer diameter is 140 mm to 200 mm, and
the inner diameter is 80 mm to 140 mm. Therefore, a thick,
long-life cylindrical sputtering target can be manufactured. In
addition, the maximum bending amount is 1.5 mm or less. Therefore,
a reduction in thickness caused by cutting can be suppressed.
[0029] According to the present invention, a method of
manufacturing a cylindrical sputtering target is provided,
including: a melting and casting step of obtaining an ingot in
which a purity of copper is 99.99 mass % to 99.9995 mass %, an Al
content is 0.5 mass ppm or lower, a Si content is 1 mass ppm or
lower, a C content is 1 mass ppm or lower, an O content is 2 mass
ppm or lower, a H content is 1 mass ppm or lower, and a S content
is 5 mass ppm or lower; a hot extrusion step of performing hot
extrusion on the ingot to obtain a hot extruded material for a
cylindrical sputtering target; and a machining step of performing
machining on the hot extruded material for a cylindrical sputtering
target.
[0030] In the method of manufacturing a cylindrical sputtering
target according to the embodiment having the above-described
configuration machining is performed on the hot extruded material
for a cylindrical sputtering target obtained in the hot extrusion
step. In this method, a cooling step is not necessary, and the
manufacturing costs can be reduced. In addition, bending or warping
caused by a cooling step does not occur, the inner peripheral
surface and the outer peripheral surface of the hot extruded
material for a cylindrical sputtering target is not cut more than
necessary, and thus a thick cylindrical sputtering target can be
obtained.
Advantageous Effects of Invention
[0031] According to the present invention, it is possible to
provide a thick and long-life hot extruded material for a
cylindrical sputtering target with which the occurrence of abnormal
discharge is suppressed such that a film can be stably formed, and
a method of manufacturing a cylindrical sputtering target using the
hot extruded material for a cylindrical sputtering target.
BRIEF DESCRIPTION OF DRAWINGS
[0032] FIG. 1 is a schematic diagram showing a hot extruded
material for a cylindrical sputtering target according to an
embodiment of the present invention. FIG. 1(a) is a cross-sectional
view perpendicular to an axis direction, and FIG. 1(b) is a side
view.
[0033] FIG. 2 is a diagram showing a method of measuring a maximum
bending amount of the hot extruded material for a cylindrical
sputtering target.
[0034] FIG. 3 is a flow chart showing a method of manufacturing a
hot extruded material for a cylindrical sputtering target and a
method of manufacturing a cylindrical sputtering target according
to an embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0035] Hereinafter, a hot extruded material for a cylindrical
sputtering target according to an embodiment of the present
invention will be described with reference to the accompanying
drawings.
[0036] A hot extruded material 10 for a cylindrical sputtering
target according to the embodiment is a material of a cylindrical
sputtering target that is used for forming a thin film (wiring
film) formed of copper such as a glass substrate by sputtering.
[0037] The hot extruded material 10 for a cylindrical sputtering
target has a cylindrical shape as shown in FIG. 1, in which, for
example, an outer diameter D is in a range of 140
mm.ltoreq.D.ltoreq.200 mm, an inner diameter d is in a range of 80
mm.ltoreq.d.ltoreq.140 mm, and a length L in the axis direction is
in a range of 900 mm.ltoreq.L.times.4000 mm. In addition, the
thickness of the hot extruded material 10 for a cylindrical
sputtering target (a difference between the outer diameter D and
the inner diameter d: D-d) is in a range of 10
mm.ltoreq.D-d.ltoreq.90 mm.
[0038] An outer peripheral surface of the hot extruded material 10
for a cylindrical sputtering target is a sputtering surface of a
cylindrical sputtering target.
[0039] In a composition of the hot extruded material 10 for a
cylindrical sputtering target, a purity of copper is in a range of
99.99 mass % to 99.9995 mass %, an Al content is 0.5 mass ppm or
lower, a Si content is 1 mass ppm or lower, a C content is 1 mass
ppm or lower, an O content is 2 mass ppm or lower, a H content is 1
mass ppm or lower, and a S content is 5 mass ppm or lower.
[0040] Further, in the embodiment, a total content of one element
or two or more elements selected from the group consisting of Ag,
As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe is in a range of 10 mass ppm to
50 mass ppm.
[0041] In the hot extruded material 10 for a cylindrical sputtering
target according to the embodiment, as shown in FIG. 1, an average
crystal grain size measured at 36 positions in total is in a range
of 10 .mu.m to 110 .mu.m and a Vickers hardness measured at the 36
positions in total is in a range of 40 Hv to 100 Hv, the 36
positions being selected by obtaining three cross-sections
perpendicular to an axis O direction from one end portion (A), an
intermediate portion (B), and another end portion (C) in the axis O
direction, setting four positions (1, 2, 3, 4) in a peripheral
direction from each of the three cross-sections, and setting three
positions in each of the four positions, the three positions
including a surface part (a), a radially 1/4 position (b) from the
surface part, and a radially 1/2 position (c) from the surface
part. In each of the 36 positions, regarding crystal grains in a
800.times.800.times.800 .mu.m region, average cut lengths of three
axes parallel to and perpendicular to the axis O direction were
measured using an optical microscope according to JIS H 0501:1986
(cut method), and an average value thereof was obtained.
[0042] In the embodiment, the one end portion and the other portion
in the axis O direction are positions at a distance of 100 mm from
respective end surfaces thereof toward the center of the hot
extruded material 10 for a cylindrical sputtering target in the
axis O direction. In addition, the intermediate portion is a center
position of the length in the axis O direction.
[0043] In addition, in the hot extruded material 10 for a
cylindrical sputtering target according to the embodiment, a weight
ratio of acid-insoluble residues is 1.5 mass ppm or lower, and the
number of acid-insoluble residues having a grain size of 5 .mu.m or
more is 15000 residues/Cu 1 g or less.
[0044] The evaluation of the acid-insoluble residues is performed
in the following procedure.
[0045] First, a predetermined amount (for example, 100 g) of a
sample is obtained from the hot extruded material 10 for a
cylindrical sputtering target having a washed surface and is heated
and dissolved in a heated nitric acid solution. The solution is
cooled to room temperature and is filtered through a filter to
collect residues.
[0046] The filter in which the residues are collected is weighed to
measure the residue mass of the residues. A ratio of the weight of
the residues to the weight of the dissolved sample is calculated.
In this way, the amount (weight ratio) of the acid-insoluble
residues obtained by heating and dissolving hot extruded material
10 for a cylindrical sputtering target in the nitric acid solution
is measured.
[0047] Next, the filter in which the residues are collected is
observed using a scanning electron microscope to obtain an SEM
image. The SEM image is analyzed to measure the sizes and number of
acid-insoluble residues. The number of acid-insoluble residues
having a grain size of 5 .mu.m or more is obtained.
[0048] In this way, in the hot extruded material 10 for a
cylindrical sputtering target, the number of acid-insoluble
residues having a grain size of 5 .mu.m or more per 1 g of Cu is
measured.
[0049] Further, in the hot extruded material 10 for a cylindrical
sputtering target according to the embodiment, a maximum bending
amount is 1.5 mm or less.
[0050] The maximum bending amount is measured as follows. As shown
in FIG. 2, the hot extruded material 10 for a cylindrical
sputtering target is disposed on a horizontal and flat surface
plate 20 such that the axis O of the hot extruded material 10 for a
cylindrical sputtering target is parallel to a surface of the
surface plate 20. In this state, a maximum value of a clearance S
with the surface plate 20 is measured using a clearance gauge. This
measurement of the clearance S is performed at four positions at an
interval of 90.degree. along the peripheral direction of the hot
extruded material 10 for a cylindrical sputtering target, and an
average value thereof is set as "maximum bending amount".
[0051] Hereinafter, regarding the hot extruded material 10 for a
cylindrical sputtering target according to the embodiment, the
reason why the composition, the average crystal grain size, the
Vickers hardness, the weight ratio and number of acid-insoluble
residues, and the maximum bending amount are limited as described
above will be described.
(Purity of Copper: 99.99 Mass % to 99.9995 Mass %)
[0052] In a case where a wiring film (copper film) is formed by
sputtering, it is preferable that impurities be reduced as much as
possible to suppress abnormal discharge (arcing). In a case where
the purity of copper is lower than 99.99 mass %, abnormal discharge
frequently occurs due to impurities such that a film may not be
stably formed. On the other hand, in a case where the purity of
copper is higher than 99.9995 mass %, a complicated purification
treatment is necessary, and a significant increase in manufacturing
costs can be suppressed.
[0053] Due to the above-described reasons, in the embodiment, the
purity of copper is set in a range of 99.99 mass % to 99.9995 mass
%. In order to suppress the occurrence of abnormal discharge, the
lower limit of the purity of copper is preferably 99.993 mass % or
higher and more preferably 99.995 mass % or higher. In addition, in
order to further suppress a significant increase in manufacturing
costs, the upper limit of the purity of copper is preferably
99.9990 mass % or lower and more preferably 99.9985 mass % or
lower.
[0054] The purity of copper in the embodiment is a numerical value
excluding gas components such as O, H, N, S, and C.
[0055] That is, the contents of O, H, N, S, and C are measured
using the following methods of O: inert gas fusion-infrared
absorption method, H inert gas fusion-thermal conductivity method,
N: inert gas fusion-thermal conductivity method, S: glow-discharge
mass spectrometry, and C: combustion-infrared absorption method. In
a case where the purity of copper is calculated, the contents of O,
H, N, S, and C are not reduced, and the contents other elements are
reduced to calculate the purity of copper.
(Al: 0.5 Mass Ppm or Lower)
[0056] Al is an element that is likely to form an oxide, a carbide,
a nitride, or the like, and thus tends to remain as foreign matter
in the sputtering target.
[0057] Therefore, in the embodiment, by limiting the Al content to
be 0.5 mass ppm or lower, even in a case where the purity of Cu is
99.99 mass % or higher, abnormal discharge (arcing) during film
formation is suppressed. The Al content is more preferably 0.2 mass
ppm or lower. The lower limit value of the Al content is not
limited, and is preferably 0.001 mass ppm and more preferably 0
mass ppm. The Al content is measured using a glow-discharge mass
spectrometer (VG-9000, manufactured by VG Elemental) according to
the analytical procedure of ASTM.
(Si: 1 Mass Ppm or Lower)
[0058] Si is an element that is likely to form an oxide, a carbide,
a nitride, or the like, and thus tends to remain as foreign matter
in the sputtering target.
[0059] Therefore, in the embodiment, by limiting the Si content to
be 1 mass ppm or lower, even in a case where the purity of Cu is
99.99 mass % or higher, abnormal discharge (arcing) during film
formation is suppressed. The Si content is more preferably 0.8 mass
ppm or lower. The lower limit value of the Si content is not
limited, and is preferably 0.001 mass ppm and more preferably 0
mass ppm. The Si content is measured using a glow-discharge mass
spectrometer (VG-9000, manufactured by VG Elemental) according to
the analytical procedure of ASTM.
(C: 1 Mass Ppm or Lower)
[0060] C reacts with another impurity element to form a carbide and
is likely to remain as foreign matter in the sputtering target. In
addition, C is likely to remain in the sputtering target even when
used as a single substance, and thus may cause abnormal discharge
(arcing) to occur.
[0061] Therefore, in the embodiment, by limiting the C content to
be 1 mass ppm or lower, abnormal discharge (arcing) during film
formation is suppressed. The C content is more preferably 0.8 mass
ppm or lower. The lower limit value of the C content is not
limited, and is preferably 0.1 mass ppm and more preferably 0 mass
ppm. The C content is measured using CSLS 600 (manufactured by
LECO) according to a combustion-infrared absorption method (JIS Z
2615).
(O: 2 Mass Ppm or Lower/H: 1 Mass Ppm or Lower)
[0062] In a case where a film is formed using the sputtering
target, sputtering is performed in a vacuum atmosphere. Therefore,
in a case where large amounts of the gas components are present,
the degree of vacuum decreases during film formation, which may
induce abnormal discharge (arcing). In addition, particles are
formed due to abnormal discharge, and thus the quality of a
high-purity copper film may deteriorate.
[0063] Therefore, in the embodiment, the O content is limited to be
2 mass ppm or lower, and the H content is limited to be 1 mass ppm
or lower. The O content is more preferably 1 mass ppm or lower, and
the H content is more preferably 0.8 mass ppm or lower. The lower
limit value of the O content is not limited, and is preferably 0.5
mass ppm and more preferably 0 mass ppm. The O content is measured
using TCEN 600 (manufactured by LECO) according to an inert gas
fusion-infrared absorption method (JIS H 1067). The lower limit
value of the H content is not limited, and is preferably 0.5 mass
ppm and more preferably 0 mass ppm. The H content is measured using
RHEN 602 (manufactured by LECO) according to an inert gas
fusion-thermal conductivity method (JIS Z 2614).
(S: 5 Mass Ppm or Lower)
[0064] S is an element that reacts with another impurity element to
form a sulfide and is likely to remain as foreign matter in the
sputtering target. In addition, in a case where S is present as a
single substance, S is gasified and ionized during film formation
such that the degree of vacuum decreases, which may induce abnormal
discharge (arcing).
[0065] Therefore, in the embodiment, the S content is limited to be
5 mass ppm or lower. The S content is more preferably 4 mass ppm or
lower. The lower limit value of the S content is not limited, and
is preferably 0.01 mass ppm and more preferably 0 mass ppm. The S
content is measured using a glow-discharge mass spectrometer
(VG-9000, manufactured by VG Elemental) according to the analytical
procedure of ASTM.
(Total Content of One Element or Two or More Elements Selected from
Group Consisting of Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe: 10 Mass
Ppm to 50 Mass Ppm)
[0066] The above-described elements Ag, As, Pb, Sb, Bi, Cd, Sn, Ni,
and Fe act to reduce the crystal grain size. On the other hand, in
a case where large amounts of the above-described elements are
present, a large amount of particles are formed during film
formation, and a film may not be stably formed. The content of the
above-described elements is determined by optionally adjusting the
addition amounts of the elements Therefore, in the hot extruded
material 10 for a cylindrical sputtering target according to the
embodiment, in order to reduce the crystal grain size, the total
content of the above-described elements is preferably in a range of
10 mass ppm to 50 mass ppm. In order to reliably obtain the effect
of reducing the crystal grain size, the lower limit of the total
content of one element or two or more elements selected from the
group consisting of Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe is
preferably 15 mass ppm or higher and more preferably 20 mass ppm or
higher. In addition, in order to reliably suppress particle
formation, the upper limit of the total content of one element or
two or more elements selected from the group consisting of Ag, As,
Pb, Sb, Bi, Cd, Sn, Ni, and Fe is preferably 45 mass ppm or lower
and more preferably 40 mass ppm or lower.
[0067] The content of Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe is
measured using a glow-discharge mass spectrometer (VG-9000,
manufactured by VG Elemental) according to the analytical procedure
of ASTM.
(Average Crystal Grain Size: 10 .mu.m to 110 .mu.m)
[0068] The sputtering rate varies depending on crystal
orientations. Therefore, as sputtering progresses, unevenness
corresponding to crystal grains is formed on the sputtering surface
due to a variation in sputtering rate.
[0069] In a case where the average crystal grain size is more than
110 .mu.m, unevenness formed on the sputtering surface becomes
significant, electric charges are concentrated on protruded
portions, and abnormal discharge is likely to occur. On the other
hand, in a case where the average crystal grain size is less than
10 .mu.m, the manufacturing costs significantly increase.
[0070] Therefore, in the embodiment, the average crystal grain size
is limited to be in a range of 10 min to 110 .mu.m. In order to
reliably suppress the unevenness of the sputtering surface and to
reliably suppress abnormal discharge as sputtering progresses, the
average crystal grain size is preferably 100 .mu.m or less and more
preferably 80 .mu.m or less. In addition, in order to suppress a
significant increase in manufacturing costs, the average crystal
grain size is preferably 20 .mu.m or more and more preferably 30
.mu.m or more.
(Vickers Hardness: 40 Hv to 100 Hv)
[0071] In the hot extruded material 10 for a cylindrical sputtering
target according to the embodiment, in a case where the Vickers
hardness is higher than 100 Hv, internal strains in crystal grains
increase, the formation of secondary electrons during sputtering is
unstable, and a film may not be stably formed. In addition, due to
internal strains, the sputtering rate varies, unevenness is formed
on the sputtering surface, and thus the number of times of micro
arc discharge may increase. On the other hand, in a case where the
Vickers hardness is lower than 40 Hv, the crystal grain size
increases. Therefore, as sputtering progresses, unevenness is
formed on the sputtering surface, and abnormal discharge is likely
to occur.
[0072] Due to the above-described reasons, in the embodiment, the
Vickers hardness is limited to be in a range of 40 Hv to 100 Hv. In
order to suppress an increase in crystal grain size and to reliably
suppress abnormal discharge, the lower limit of the Vickers
hardness is preferably 45 Hv or higher and more preferably 50 Hv or
higher. In addition, in order to make the sputtering rate uniform
and to reliably suppress unevenness in thickness and micro arc
discharge, the upper limit of the Vickers hardness of the
sputtering surface is preferably 95 Hv or lower, and more
preferably 90 Hv or lower.
[0073] The Vickers hardness can be measured at all the 36
positions, which are the same as that in the measurement of the
average crystal grain size, using a Vickers hardness tester
according to JIS Z 2244.
(Weight Ratio and Number of Acid-Insoluble Residues)
[0074] In the hot extruded material 10 for a cylindrical sputtering
target according to the embodiment, in a case where acid-insoluble
residues are present, abnormal discharge is likely to occur due to
the acid-insoluble residues. In particular, electric charges are
concentrated on residues having a grain size of 5 .mu.m or more,
and abnormal discharge may occur due to the residues.
[0075] Therefore, in the embodiment, the weight ratio of
acid-insoluble residues is limited to be 1.5 mass ppm or lower, and
the number of acid-insoluble residues having a grain size of 5
.mu.m or more is limited to be 15000 residues/Cu 1 g or less.
[0076] In order to further suppress the occurrence of abnormal
discharge, the weight ratio of acid-insoluble residues is
preferably 1.2 mass ppm or lower, and the number of acid-insoluble
residues having a grain size of 5 .mu.m or more is preferably 12000
residues/Cu 1 g or less.
[0077] The lower limit value of the weight ratio of residues is not
particularly limited and may be 0.5 mass ppm, and the lower limit
value of the number of acid-insoluble residues having a grain size
of 5 .mu.m or more may be 500 residues/Cu 1 g.
(Maximum Bending Amount)
[0078] In the hot extruded material 10 for a cylindrical sputtering
target according to the embodiment, in a case where the maximum
bending amount increases, the cutting allowance during cutting
increases, it may be difficult to manufacture a thick cylindrical
sputtering target. In addition, the yield decreases, and thus the
manufacturing costs may significantly increase.
[0079] Therefore, in the embodiment, the maximum bending amount is
limited to be 1.5 mm or less. In order to reliably cut the cutting
allowance during cutting, the maximum bending amount is preferably
1.2 mm or less and more preferably 1.0 mm or less. The lower limit
value of the maximum bending amount is not particularly limited and
may be 0.1 mm.
[0080] Next, a method of manufacturing the hot extruded material 10
for a cylindrical sputtering target having the above-described
configuration, and a method of manufacturing a cylindrical
sputtering target using the hot extruded material 10 for a
cylindrical sputtering target will be described with reference to a
flowchart of FIG. 3.
[0081] In the embodiment, the method includes: a melting and
casting step S01 of obtaining an ingot having a predetermined
composition; a hot extrusion step S02 of performing hot extrusion
on the obtained ingot to manufacture the hot extruded material 10
for a cylindrical sputtering target; and a machining step S03 of
performing machining on the obtained hot extruded material 10 for a
cylindrical sputtering target.
[0082] In the melting and casting step S01, a cylindrical ingot is
continuously cast using various casting machines such as a vertical
continuous casting machine, a horizontal continuous casting
machine, or a semi-continuous casting machine and is cut into a
predetermined length.
[0083] In the melting and casting step S01, in order to reduce the
content of impurity elements such as Al or Si, oxygen is supplied
into a trough through which molten copper passes to produce oxides
and to remove the impurity elements as solids, and then the molten
copper is deoxidized. In addition, in the embodiment, the ingot as
a product is obtained when the behavior of impurity elements is
stable after 5 t from the start of casting.
[0084] In the hot extrusion step S02, extrusion is performed on the
cylindrical ingot at a predetermined temperature to manufacture the
hot extruded material 10 for a cylindrical sputtering target.
[0085] In the embodiment, the hot extrusion temperature is set in a
range of 500.degree. C. to 600.degree. C. The hot extrusion
temperature is more preferably 520.degree. C. to 580.degree. C. In
addition, after the extrusion, soaking is performed in a soaking
zone including heating devices such as a heater, and then rapid
cooling is performed.
[0086] In the soaking zone, a holding temperature is in a range of
530.degree. C. to 600.degree. C., and a holding time is set in a
range of 1 min to 15 min. The holding temperature is preferably
540.degree. C. to 580.degree. C., and the holding time is 2 min to
10 min. In addition, during the rapid cooling, a cooling rate is
set in a range of 30.degree. C./min to 60.degree. C./min. The
cooling rate is more preferably 35.degree. C./min to 55.degree.
C./min.
[0087] In this way, the hot extruded material 10 for a cylindrical
sputtering target according to the embodiment is obtained.
[0088] In addition, in the embodiment, machining is performed on
the hot extruded material 10 for a cylindrical sputtering target to
manufacture a cylindrical sputtering target having a predetermined
size. That is, in the embodiment, the cylindrical sputtering target
is manufactured without performing cold working on the hot extruded
material 10 for a cylindrical sputtering target.
[0089] The cylindrical sputtering target rotates around the axis
during use in a sputtering device, and an outer peripheral surface
thereof is used as a sputtering surface.
[0090] In the hot extruded material 10 for a cylindrical sputtering
target according to the embodiment having the above-described
configuration, as shown in FIG. 1, an average crystal grain size
measured at 36 positions in total is in a range of 10 .mu.m to 110
.mu.m and a Vickers hardness measured at the 36 positions in total
is in a range of 40 Hv to 100 Hv, the 36 positions being selected
by obtaining three cross-sections perpendicular to an axis O
direction from one end portion (A), an intermediate portion (B),
and another end portion (C) in the axis O direction, setting four
positions (1, 2, 3, 4) in a peripheral direction from each of the
three cross-sections, and setting three positions in each of the
four positions, the three positions including a surface part (a), a
radially 1/4 position (b) from the surface part, and a radially 1/2
position (c) from the surface part. Therefore, there is no
variation in crystal grain size and Vickers hardness, and the hot
extruded material 10 for a cylindrical sputtering target can be
used as a cylindrical sputtering target only after performing
machining thereon.
[0091] As described above, cold working (expansion) is not
necessary. Therefore, a thick cylindrical sputtering target can be
obtained, and the lifetime thereof can be increased.
[0092] In addition, in the embodiment, the Al content is 0.5 mass
ppm or lower, the Si content is 1 mass ppm or lower, the C content
is 1 mass ppm or lower, the O content is 2 mass ppm or lower, the H
content is 1 mass ppm or lower, and the S content is 5 mass ppm or
lower. Therefore, the occurrence of abnormal discharge caused by
foreign matter including the impurities can be suppressed, and a
film can be stably formed.
[0093] In addition, in the hot extruded material 10 for a
cylindrical sputtering target according to the embodiment, the
total content of one element or two or more elements selected from
the group consisting of Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe is
10 mass ppm or higher. Therefore, the crystal grain size can be
reduced, and a variation in average crystal grain size and Vickers
hardness can be further suppressed.
[0094] On the other hand, the total content of one element or two
or more elements selected from the group consisting of Ag, As, Pb,
Sb, Bi, Cd, Sn, Ni, and Fe is limited to be 50 mass ppm or lower.
Therefore, the occurrence of abnormal discharge caused by the
elements can be reliably reduced.
[0095] Further, in the hot extruded material 10 for a cylindrical
sputtering target according to the embodiment, the weight ratio of
acid-insoluble residues is 1.5 mass ppm or lower, and the number of
acid-insoluble residues having a grain size of 5 .mu.m or more is
limited to be 15000 residues/Cu 1 g or less. Therefore, particle
formation can be suppressed during film formation.
[0096] In addition, in the hot extruded material 10 for a
cylindrical sputtering target according to the embodiment, the
outer diameter is 140 mm to 200 mm, the inner diameter is 80 mm to
140 mm, and the length is 900 mm to 4000 mm. Therefore, a
relatively thick and long-life cylindrical sputtering target can be
manufactured.
[0097] Further, the maximum bending amount is 1.5 mm or less.
Therefore, a reduction in thickness caused by cutting can be
suppressed.
[0098] Further, the method of manufacturing a cylindrical
sputtering target according to the embodiment includes the
machining step S03 of performing machining on the obtained hot
extruded material 10 for a cylindrical sputtering target according
to the embodiment. In this method, a cooling step is not necessary,
and the manufacturing costs can be reduced. In addition, bending or
warping caused by a cooling step does not occur, the inner
peripheral surface and the outer peripheral surface of the hot
extruded material 10 for a cylindrical sputtering target is not cut
more than necessary, and thus a thick cylindrical sputtering target
can be obtained.
[0099] Hereinabove, the embodiment of the present invention has
been described. However, the present invention is not limited to
the embodiment, and various modifications can be made within a
range not departing from the technical ideas of the present
invention.
[0100] For example, in the embodiment, the size of the hot extruded
material for a cylindrical sputtering target is not limited to that
of the embodiment and may be another size.
Examples
[0101] Hereinafter, the results of an experiment for verifying the
effectiveness of the present invention will be described.
[0102] First, in a vertical continuous casting machine, a
cylindrical ingot formed of copper having a composition shown in
Table 1 was obtained by using electrolytic copper having a purity
of 99.99 mass % or higher as a raw material. By analyzing the
components of the electrolytic copper as a raw material before
melting and casting, the contents of Ag, As, Pb, Sb, Bi, Cd, Sn,
Ni, and Fe were adjusted. In addition, Ag, As, Pb, Sb, Bi, Cd, Sn,
Ni, and Fe were optionally added to molten alloy to adjust the
contents thereof. In Examples 1-18 and Comparative Example 1,
impurities such as Al or Si were removed as described above. On the
other hand, in Comparative Examples 2 and 3, impurities were not
removed.
[0103] The ingot was heated to a treatment temperature shown in
Table 2 to perform hot extrusion. As a result, a hot extruded
material for a cylindrical sputtering target (outer diameter: 173
mm, inner diameter: 125 mm) was obtained.
[0104] In the Example 1-18, after the extrusion, the ingot was
caused to pass through a soaking zone (holding temperature:
580.degree. C., holding time: 5 min) and then was cooled at a
cooling rate shown in Table 2. On the other hand, in Comparative
Example 1-3, a soaking zone was not provided, and after the
extrusion, the ingot was cooled at a cooling rate shown in Table
2.
[0105] Machining was performed on the hot extruded material for a
cylindrical sputtering target obtained as described above. As a
result, a cylindrical sputtering target (outer diameter: 170 mm,
inner diameter 120 mm, length: 600 mm) was manufactured.
[0106] Regarding the hot extruded material for a cylindrical
sputtering target and the cylindrical sputtering target, the
following evaluations were performed.
<Analysis of Impurity Elements and Respective Elements>
[0107] Impurity elements (Al, Si, and S) other than 0, H, and C and
respective elements including Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and
Fe were analyzed using a glow-discharge mass spectrometer (VG-9000,
manufactured by VG Elemental). The analysis was performed according
to the analytical procedure of ASTM.
[0108] The analysis of O was performed using an inert gas
fusion-infrared absorption method (JIS H 1067). Specifically, the
analysis was performed using TCEN 600 (manufactured by LECO)
according to JIS Z 2613.
[0109] The analysis of H was performed using an inert gas
fusion-thermal conductivity method. Specifically, the analysis was
performed using RHEN 602 (manufactured by LECO) according to JIS Z
2614.
[0110] The analysis of C was performed using a combustion-infrared
absorption method. Specifically, the analysis was performed using
CSLS 600 (manufactured by LECO) according to JIS Z 2615.
[0111] The purity of copper shown in Table 1 is a value obtained by
subtracting the sum of the contents of the respective elements
other than gas components, the Al content and the Si content from
100 mass % of the obtained hot extruded material for a cylindrical
sputtering target.
<Average Crystal Grain Size of Hot Extruded Material for
Cylindrical Sputtering Target>
[0112] As shown in FIG. 1, a crystal grain size was measured at 36
positions in total, and an average crystal grain size thereof was
calculated, the 36 positions being selected by obtaining three
cross-sections perpendicular to an axis direction from one end
portion (A), an intermediate portion (B), and another end portion
(C) in the axis direction, setting four positions (1, 2, 3, 4) in a
peripheral direction from each of the three cross-sections, and
setting three positions in each of the four positions, the three
positions including a surface part (a), a radially 1/4 position (b)
from the surface part, and a radially 1/2 position (c) from the
surface part. The crystal grain size was measured according to JIS
H0501:1986 (cutting method) after observing a microstructure with
an optical microscope. The evaluation results are shown in Table
2.
<Vickers Hardness of Hot Extruded Material for Cylindrical
Sputtering Target>
[0113] As shown in FIG. 1, a Vickers hardness was measured at 36
positions in total, and an average value thereof was calculated,
the 36 positions being selected by obtaining three cross-sections
perpendicular to an axis direction from one end portion (A), an
intermediate portion (B), and another end portion (C) in the axis
direction, setting four positions (1, 2, 3, 4) in a peripheral
direction from each of the three cross-sections, and setting three
positions in each of the four positions, the three positions
including a surface part (a), a radially 1/4 position (b) from the
surface part, and a radially 1/2 position (c) from the surface
part. The Vickers hardness was measured using a Vickers hardness
tester according to JIS Z 2244. The evaluation results are shown in
Table 2.
<Acid-Insoluble Residues>
[0114] A measurement sample was etched with nitric acid to remove
impurities attached to the surface. Next, 100 g of the sample was
weighed. This sample was heated and dissolved in a nitric acid
solution. The heating temperature was 60.degree. C. This operation
was repeated. Next, the sample was cooled to room temperature and
was filtered through a filter to collect residues.
[0115] The filtering was performed using a polycarbonate filter
(pore size: 0.4 .mu.m). The polycarbonate filter in which the
residues were collected was weighed using an electronic balance in
a clean room to measure the residue mass of the residues, and a
weight ratio of acid-insoluble residue was calculated. The
evaluation results are shown in Table 2.
[0116] In addition, a grain size distribution of the acid-insoluble
residue was measured. The filter in which the residues were
collected was observed using a scanning electron microscope to
obtain an SEM image. The image was input to a personal computer and
was binarized and analyzed using image analysis software (WinRoof
software). The projected area of a residue was measured, and the
diameter (equivalent circle diameter) of a circle having the same
area as the projected area was calculated. This equivalent circle
diameter was used as a grain size of the residue. The number of
acid-insoluble residues having a grain size of 5 .mu.m or more was
measured. The evaluation results are shown in Table 2.
<Sputtering Test>
[0117] Using the obtained cylindrical sputtering target, a
sputtering test was performed under the following conditions, and
the number of times of abnormal discharge was counted using an
arcing counter equipped in a sputtering device. The sputtering test
was performed under two conditions of "Ar gas" and "N.sub.2 gas"
regarding an atmosphere gas. The evaluation results are shown in
Table 2.
[0118] Power source: direct current type
[0119] Sputtering power: 600 W
[0120] Sputtering pressure: 0.2 Pa
[0121] Sputtering time: 8 hours
[0122] Peak vacuum degree: 4.times.10.sup.-5 Pa or lower
[0123] Atmosphere gas composition: Ar gas/N.sub.2 gas
<Tearing>
[0124] In a case where machining was performed on the hot extruded
material for a cylindrical sputtering target, the surface was
observed by visual inspection to determine whether or not scratches
or unevenness was formed on the surface. In a case where a scratch
or a torn portion was not necessary to be repaired and had a depth
of 0.5 mm or less and had a length of less than 5 mm or less, the
cylindrical sputtering target was evaluated as A. In a case where a
scratch or a torn portion had a depth of more than 0.5 mm and had a
length of more than 5 mm, the cylindrical sputtering target was
evaluated as B. The evaluation results are shown in Table 2.
<Maximum Bending Amount>
[0125] According to the embodiment and the method shown in FIG. 2,
the maximum bending amount of the hot extruded material for a
cylindrical sputtering target was measured. The evaluation results
are shown in Table 2.
TABLE-US-00001 TABLE 1 Impurities and Gas Components (mass ppm)
Contents of Respective Elements (mass ppm) Purity of Copper Al Si C
0 H S Ag As Pb Bi Cd Sn Ni Fe Total Content (mass %) Example 1 0.04
0.5 0.5 2.0 0.9 3 0.1 <1 <1 <1 <1 <1 2 2 4.1 99.9995
2 0.14 0.2 0.3 <0.5 <0.5 4 0.2 <1 <1 <1 <1 <1
3 2 5.2 99.9994 3 0.08 0.1 0.2 1.5 1.0 3 0.5 <1 <1 <1
<1 <1 4 5 9.5 99.9990 4 0.48 0.5 1.0 <0.5 <0.5 3 20 1
10 1 2 10 10 20 74 99.9925 5 0.02 0.5 0.5 <0.5 <0.5 4 10
<1 <1 <1 <1 <1 1 1 12 99.9987 6 0.05 1.0 0.5 <0.5
<0.5 3 13 11 2 4 <1 <1 1 1 32 99.9966 7 0.50 1.0 0.5
<0.5 <0.5 3 13 <1 11 <1 <1 <1 1 1 26 99.9972 8
0.06 0.9 0.5 <0.5 1.0 4 13 3 2 8 <1 <1 1 1 28 99.9971 9
0.12 0.7 0.5 <0.5 <0.5 4 13 3 2 <1 9 <1 1 1 29 99.9970
10 0.15 0.6 0.5 <0.5 <0.5 3 13 <1 <1 <1 <1 7 1 1
22 99.9977 11 0.04 0.6 0.5 2.0 0.8 3 13 <1 <1 <1 <1
<1 13 7 33 99.9966 12 0.50 0.9 1.0 1.6 0.8 4 13 <1 <1
<1 <1 <1 <1 9 22 99.9976 13 0.12 0.5 0.5 <0.5
<0.5 5 12 <1 <1 <1 <1 <1 13 12 37 99.9962 14 0.12
0.5 0.5 <0.5 <0.5 3 13 <1 <1 <1 <1 <1 1 1 15
99.9984 15 0.15 0.2 0.5 <0.5 <0.5 3 12 <1 <1 <1
<1 <1 1 1 14 99.9985 16 0.09 0.1 0.5 <0.5 <0.5 3 14
<1 <1 <1 <1 <1 1 1 16 99.9983 17 0.07 0.8 0.5
<0.5 <0.5 5 15 <1 <1 <1 <1 <1 1 1 17 99.9982
18 0.10 1.0 0.5 <0.5 <0.5 3 13 <1 <1 <1 <1 <1
1 1 15 99.9983 Comparative 1 1.5 1.5 2.0 10.0 1.4 9 15 <1 7
<1 <1 <1 9 10 41 99.9955 Example 2 2.0 1.4 2.0 5.2 1.5 8
15 <1 8 <1 <1 <1 10 10 43 99.9953 3 2.0 1.5 2.0 4.1 1.3
10 15 <1 5 <1 <1 5 7 10 42 99.9954
TABLE-US-00002 TABLE 2 Acid-Insoluble Residues Number of Casting
acid- Number of Times Step Extrusion Step Vickers Weight insoluble
of Abnormal Maximum Removal Treatment Cooling Crystal Hard- Ratio
residues Discharge Bending of Temperature Soaking Rate Grain Size
ness mass Residues/ Ar N.sub.2 Amount Impurities .degree. C. Zone
.degree. C./sec .mu.m Hv ppm Cu 1 g times/h times/h Tearing mm
Examples 1 Performed 510 Provided 35 84 69 0.8 12000 1 2 A 0.7 2
Performed 580 Provided 35 89 65 0.6 8000 1 1 A 0.7 3 Performed 550
Provided 40 60 70 0.3 4500 1 2 A 0.7 4 Performed 510 Provided 42 24
90 0.4 4000 2 3 A 0.7 5 Performed 520 Provided 38 29 86 0.5 4200 0
0 A 0.8 6 Performed 540 Provided 48 45 81 0.4 4000 0 0 A 0.7 7
Performed 550 Provided 55 51 71 0.8 7900 0 0 A 0.6 8 Performed 560
Provided 51 79 60 0.6 8400 0 0 A 0.7 9 Performed 580 Provided 49 89
55 0.5 3900 0 0 A 0.7 10 Performed 590 Provided 51 98 51 0.8 13000
1 1 A 0.8 11 Performed 540 Provided 39 37 90 0.8 12100 1 1 A 0.6 12
Performed 550 Provided 31 29 59 1.2 13900 2 2 A 0.7 13 Performed
550 Provided 58 27 64 0.6 8300 0 1 A 0.8 14 Performed 550 Provided
55 59 78 0.7 9100 0 1 A 0.7 15 Performed 520 Provided 38 31 95 1.0
13000 1 1 A 0.7 16 Performed 520 Provided 39 35 89 1.9 14500 3 3 A
0.7 17 Performed 530 Provided 39 58 79 0.9 21400 3 4 A 0.8 18
Performed 590 Provided 44 98 49 0.6 8200 0 0 A 2.3 Comparative 1
Performed 450 Not 48 Since Extrusion could not be Performed,
Evaluations were not Performed Example Provided 2 Not 750 Not 55
110 40 2.0 30000 121 81 B 1.2 Performed Provided 3 Not 800 Not 34
120 32 1.9 29000 112 73 B 1.9 Performed Provided
[0126] In Comparative Example 1, the heating temperature in the
extrusion step was lower than 450.degree. C., and thus extrusion
could not be performed. Therefore, the subsequent evaluations were
stopped.
[0127] In Comparative Examples 2 and 3, the contents of Al and Si
as impurities and the contents of C, O, H, and S as gas components
were outside of the ranges of the present invention, the number of
acid-insoluble residues was large, and the number of times of
abnormal discharge was extremely large. In addition, tearing
frequently occurred during cutting.
[0128] On the other hand, in all the Examples, the number of times
of abnormal discharge was small, and a film could be stably formed.
In addition, the occurrence of tearing during cutting was small,
and machinability was excellent.
[0129] It was verified from the above results that, according to
Examples, it is possible to provide a thick and long-life hot
extruded material for a cylindrical sputtering target with which
abnormal discharge is suppressed such that a film can be stably
formed.
REFERENCE SIGNS LIST
[0130] 10: HOT EXTRUDED MATERIAL FOR A CYLINDRICAL SPUTTERING
TARGET
* * * * *